Field of the Invention
The present invention relates to a golf club shaft.
Description of the Related Art
A so-called carbon shaft has been known as a golf club shaft. A sheet winding process has been known as a method for manufacturing the carbon shaft. In the sheet winding process, a laminated constitution is obtained by winding a prepreg around a mandrel.
The prepreg includes a resin and a fiber. Many types of prepregs exist. A plurality of prepregs having different resin contents have been known. In the present application, the prepreg is also referred to as a prepreg sheet or a sheet.
In the sheet winding process, the type of a sheet, the disposal of the sheet, and the orientation of a fiber can be selected. The sheet winding process is excellent in a degree of freedom in design.
Japanese Patent Application Laid-Open No. 2012-239574 (US2012/0295734) discloses a golf club shaft having a shaft weight of equal to or greater than 52 g and a ratio (Lg/Ls) of a center of gravity of the shaft of equal to or greater than 0.52 but equal to or less than 0.65. This shaft has an excellent flight distance performance.
Japanese Patent Application Laid-Open No. 2014-76142 discloses a golf club shaft which includes a tip end partial layer having a glass fiber reinforced layer.